Nutritional and antioxidant potential of seeds from two Cucurbitaceae species from Senegal

Abstract

Cucurbits are largely grown in tropical and subtropical areas for nutritional and medicinal purposes. In Senegal, two species, watermelon (Citrullus lanatus) and pumpkin (Cucurbita pepo), are cultivated and their use include consumption of flesh or the whole fruit. In general, people don’t give importance to seeds which can have nutritional properties of great interest. Hence, the relevance of this study whose objective is to assess the nutritional and therapeutic properties of seeds. For that purpose, the seeds of watermelon and pumpkin were air-dried, manually shelled, ground, and subjected to assays including physicochemical determination, characterization of oils, phytochemical screening and antioxidant analysis. Proteins (28.46 - 32.85 %), fat (36.3 - 39.7 %) and carbohydrates (23.6 - 13.9 %) were the main chemical components found in watermelon and pumpkin seeds. Micro-elements such as potassium, magnesium, phosphorous, calcium, and iron were also found with potassium showing the highest levels as 1026.07 and 635.00 mg/100 g for watermelon and pumpkin, respectively. Magnesium and phosphorous were the following minerals in terms of level content. The unsaturated fatty acids (UFAs) were predominant in seed oils with the linoleic acid most representative as 73.01 and 35.90% for watermelon and pumpkin, respectively. From the saturated fatty acids (SFAs), the palmitic acid was the most important. Phytochemical components in seeds include the presence of alkaloids, cardiac glycosides, flavonoids, and tannins in the ethanolic extracts of pumpkin and watermelon seeds. Regarding to the radical scavenging activity, relatively close values have been obtained for fractions from the ethanolic watermelon extract, the aqueous fraction showing the highest antioxidant activity (26.82%). For pumpkin, the highest values were registered for ethyl acetate and aqueous fractions as 36.17 and 35.36%, respectively. Therefore, seeds from watermelons and pumpkin cultivated in Senegal exhibited interesting nutritional and antioxidant properties which argue in favor of their use to overcome malnutrition issues.